DB2 Notification Log

I have seen scenario where the notification log ( db2inst1.nfy file) is of 9 GB. Now there the /home file system is full. Please suggest can I delete this file. If I delete will it going to affect the system or DB2 Automatically creates one more notification log file.

Yes, you can delete it without any danger. DB2 will spawn a new file next time it wants to write to it.
The db2diag -A <diagpath>/<instance>.nfy command will archive it with a timestamp, after which you can just zip up the archive.
There is a very useful admin view to retrieve log messages in the last 24 hours, before you archive or delete the file: sysibmadm.pdlogmsgs_last24hours
Very easy to wrap into a daily check script:

OK.
I'm simply suggesting it's worthwhile to run the query below against sysibmadm.pdlogmsgs_last24hours, every day and certainly before you archive or delete the instance notify log.
It's a very useful source of information, particularly at NOTIFYLEVEL 4.

IMHO, the instance notify log, provides very rarely additional information to db2diag.log. If you have not experienced problems the last days/weeks and you do not have an additional 1GB , you can remove it. If you have space you can use the compress utility, which will reduce those 9GB to some 1GB or so: compress instance_name.nfy.

IMHO the notify log at notify level 4 is a mine of useful information and stats on database activities, such as numbers of loads, lock escalations, not logged initially activations and so on. You do not need to experience a problem to use it - simply run the very simple SQL query I posted earlier in this thread, every day, before archiving or dropping the log.

Remember the intention of the notify log was to provide a friendlier source of information than the db2diag.log - not as a replacement, just a useful adjunct.